Question

The colour of blood is red due to the presence of
A. Magnesium
B. Cytoglobin
C. Haemoglobin
D. All of the above.

Answer 1

Hint: Red as a colour is mostly seen in compounds containing Iron-based compounds. Using this in concept, try and think of the compounds in the options and their chemical compositions.

Complete answer:
To answer this question, first, we need to know about the composition of blood. Blood is a body fluid in humans and other animals that delivers necessary substances such as nutrients and oxygen to the cells and transfers metabolic waste materials far from those similar cells. It is a liquid connective tissue made up of 55% plasma and 45% formed elements including WBCs, RBCs, and platelets. Since these living cells are suspended in plasma, blood is known as a fluid connective tissue and not just fluid.
Now, let us find the solution from the option.
Hemoglobin is iron-consisting oxygen delivering protein in the red blood cells of most of all vertebrates. It has an oxygen tying ability and provides the red colour to the blood. Each subblocks of hemoglobin is a globular protein with an inserted heme group.

Thus, the correct option is C. i.e. Haemoglobin.

Note:Vertebrate blood is bright red when its hemoglobin is oxygenated and dark red when it is deoxygenated. Some animals, such as crustaceans and mollusks, utilize hemocyanin to transport oxygen, in the place of hemoglobin. Insects and some mollusks use a fluid known as hemolymph in the replacement of blood, the difference being that hemolymph is not contained in a closed circulatory system.